Preheat oven to 350 degrees F. Line a standard size 12-cup muffin tin with paper liners. Coat lightly with nonstick cooking spray.
In a large bowl, mix flour, sugar, baking powder, baking soda, salt and cinnamon. Add mashed bananas, butter, egg, and vanilla. Mix well until all ingredients are thoroughly combined. Fold in toasted coconut. Scoop batter into muffin tin until 3/4 full.
Bake muffins for 20 to 25 minutes, or until muffin tops spring back lightly when touched.